The present invention relates to the field of removal and storage of organs with a view to their transplantation, both in humans and in animals.
More particularly, the invention relates to a method for hypothermic perfusion of a cardiac organ and to a perfusion device for carrying out the method.
Organ transplant operations, put simply, involve at least one defective organ in a living patient being replaced by the healthy and functional corresponding organ from a deceased person or, in the case of kidney transplants for example, from a living person who has agreed to donate one of his or her kidneys to a patient who is ill.
In practice, the organ or organs that are to be transplanted are removed from a donor and then stored immediately in a hypothermic state in appropriate storage devices for transporting them to the hospital establishment where the transplant operation is to be performed on the patient who is ill. This phase of storage of the transplant organs often proves critical.
One of the main problems encountered in transplantation procedures is the limited period of preservation of the transplants in a hypothermic state. Thus, for a heart transplant for example, the maximum acceptable duration between the removal of the transplant organ from the donor and its implantation in the recipient is considered to be from 4 to 6 hours. This very short time frame requires that all the participants in the transplantation procedure act with great urgency, from the personnel removing the organs to the personnel performing the transplantation itself, and including the personnel charged with transporting the organs. What is worse, this very brief period of viability of the organ between its removal and its transplantation obviously means that many transplantation operations cannot proceed because the distance between donor and recipient is too great.
Many technical proposals have hitherto been made for storing organs with a view to their transplantation.
In particular, in the first instance, there is the customary technique of organ preservation involving rapid cooling followed by cold immersion in a liquid. Unfortunately, this technique does not allow the organ to be preserved in good conditions of viability beyond 4 to 6 hours, especially in the case of a heart transplant for example. Beyond this storage period, considerable degradation is observed in the tissues of the organ that is to be transplanted.
Moreover, the literature available in the field of transplantation, particularly heart transplantation, specifies that perfusion greatly improves the conditions for survival of a heart transplant compared to preservation by immersion. However, the perfusion of heart transplants, permitting the transport of a beating heart, requires suitable apparatuses that take up a lot of space and are complex and that are provided with a system for recirculating the perfusate at body temperature and with an autonomous power source. For this reason, these apparatuses are often considered too expensive and too complex, and they have not hitherto been developed for practice in human medicine.
Document WO 2009/132018 A1 describes an organ perfusion device which is compact and involves pressurization of a liquid through the organ. However, this device pressurizes the organ itself through the effect of positive liquid pressures in the organ, which is thus “inflated” with perfusion liquid. This technique is damaging to the organic tissues and adversely affects their storage.